Abstract:The rationship between land slope and sheet flow erosion was studied on the base of erosion force of sheet flow The result indicated that by the erosion of sheet flow,the relationship between land slope and the amounts of erosion was a power funtion,the amounts of erosion increasing rate(dsF/ds)added with land slope and rainfall intensity.By the raindrop slope was roughly parabolie,that is there is a critical slope sk.when Sk.The amounts of erosion was increased with land slope,but when Sk,the amounts of erosion dereased with land slope.Finally,the mechanism of land slope effect on the sheet flow erosion was also analysed

Abstract:A field simulating runnoff test had been carried out to approach the relationships between different runoff and soil erosion,different sloplength and erosion and erosion ,types of soil utilities and erosion.Following two formulas and been set up through the analysis of the experimental results

Abstract:The results of the show that compared with control experiement,mulberry juice production increased to 5.25 times,soil erosion amount increadsed from 0.799-10.8 tonper mu(1/15 of ha)to 0 ton/mu.Soil utrient concentration in both depth of soil profiel of to 50 cm and 0 to 100cm is 90% and 100% of the control ones respectively for total N,102.9% and 126.2% for total P,103.18% and 108.01% for total K,61.5% and 61.15% for available N(hydiolysed N),139.02% and 197.72 for available P and 91.48% and 92.54% for available K.The benefit of the cultivation is 5.55 times of control one.

Abstract:Whether growing grass by acrial sowing can achieve success mainil depends on the selection of suitable grass species,which is the basis of successful aerial sowing.By the research on the properties of Onobrychis viciaefolia scop and its aerialsowing effect,the experiment results show that out of a thin seed coat,the seed of Onobrychisfolia scop is so pervious to water that the germination is quick and easy its seed is resistant to hing temperature and exposure under a violent sunlight;not only its seeding takes rootsfast,strikes root dccp,but also its root system is well-developed it grows quickly,and is branchy,the natural renewal capacity stronger. Onobrychis viviuefolia scop is a promising acrial-sowing species.

Abstract:The precent and its harmfulness of soil and water loss in red earth hilly region of south of Yangte river was discussed in this paper.Results of investigation indicate that the soil and water loss was caused by overcutting and unreasonable cropping system of farming and foresty.From a staring point of construction of rural enery resources,the ways to control soil and water loss should reform and develop current lorestory land barren hill and eroded lield,and increase vegetation cover land to improve ecosystem and prompt development of rural economy on the base of stablizing food crop production.

Abstract:The mehtods of contrat reseach and analysis of measured information about precipitation,runoff and silt discharge were employed to study the function of the silt arrester dams to detain silt in Wangmao valley as an example.Results showed that the fanction was very significant.Compared with before harmess,modulus of silt discharge decreased from 1800t/km² to 504t/km²,being97%.The target of no silt running out of the valiey was almost reached.

Abstract:Current situation of soil and water loss and producing reasons of soil degradation in Jinqu region were described in the paper. The soil degradation was caused by soil and water loss and more severe soil and water loss resulted by forest cutting over its growth rate.The overcutting lost the ecofuction of the forest.The arear of soil and water loss was over one-third of total arears of hill and mound land,and modulus of erosion was over 2500t/km².a.In order to prevent soil and water loss and soil degeneration and to establish a better ecosystem in the red soil hilly region,both combination of bilolgical and engineering measures and princeple of combination of controling the loss and developing the land resoures should be take into accout at the same time.

Abstract:Parent rock type of soil and water loss and its contributing factors and developing trend was also discussed.the rigion was divided into five kinds of soil and water loss areasaccording to the type of parrent rock,pattern and intensity of soil erosion.The five kinds are namely(1)highly intensive granite type in hill areas,(2)highly and middle intensitive sandy parple shale type in hill and mound areas,(3)highly intensitive limestone type in flat hill areas.(4)light and middle shale linestone types in hill and mound arears,and(5)highly intensitive metamorpht rock type in hill areas.According to the five different parent rock types,several corresponding measures were suggested to prevent and cure soil and cure soil and water loss and utilize the land resources in the region.

Abstract:The current status of soil and water erosion and its harmfulness were described in this paper.It was also discussed that the remarkable effects of comprchensive control of soil and water erosion of eco-environment and social economy in the county.As a result,for useful measures were suggested according to the authors practical expenience to control soil and water erosion in the region

Abstract:Results of the study that degeneration reasons of Eulalionpsis binata was taid to stortage of soil water and deficiency of nutrients.The techniques to recover the grass through increase of soil water content and fertilization were suggested by the authors in the paper on the base of their experimental reaults.

Abstract:Abstrat Small watershed is a complexed system of ecology and economy,of which the ecological system has exchange of energy,material and information with the external and could absorb negative flow of entropy,which makes the system leave balanced stable and tend to the ordered structure of the economy system man power and natural resource play predominant effects on the complexed system of ecology and economy,it is thought that to coordinate the relationship between human activity in society and economy,it is thought that to coordinate the relationship between human activity in society and economy and the economy,it is though that to coordinate the relationship between human activity in socitety and ecology and economy,it is thought that to coordinate the relationshio between human activity in society and economy and the ecological system is the fundamental problem for the harness of small watershed.Only when approaching from the factors of nature and social economy and their regineering like dynamic simulation of system and ecological principle,and finding the key problems in the system through a series of logical and nathematical analysis,might it be possible to design harness plan and dispoes the measures.It is said that the ultimate goal to harness small watershed is to establish a stable,enduring and effcient system of ecology and economy

Abstract:In this paper,the orgin and course of the research on the population carrying capacity is claborated systematically.The research course is divied into two stages,namely,the potential productivity and population carrying of land resourses,and them characterstecs and existed problems are discussed in each stage.The conclusion of the article is very improtant for us to make futher reserch perfectly on the potential producitivity and population carrying capacity of land resourses.